Natural gas-containing deposits (brown) underlie 32 of the lower 48 states.

Tracy Bank was concerned. A geochemist, she makes her living studying how water interacts with rocks. And four years ago, when she arrived at the State University of New York at Buffalo, water was definitely interacting with rocks.

Buffalo is perched on the edge of the largest known reservoir of natural gas in America, a geologic formation known as the Marcellus Shale (pdf). The 95,000-square-mile slab, which lies under sizable portions of West Virginia, New York, Ohio, and Pennsylvania, could contain up to 500 trillion cubic feet of natural gas—enough to meet the nation’s natural gas needs for at least two years. Owing to this bounty, the areas above the shale are now in the grip of an unprecedented gas-drilling boom. The gas is extracted using a method called hydraulic fracturing, or fracking, a technique that involves pumping millions of gallons of water laced with 
chemicals deep underground to blast open the shale and release the gas trapped inside. The blasting is what got Bank worried.

Fracking has already drawn considerable scrutiny from environmental groups, unhappy homeowners, and teams of lawyers who blame the drilling method for polluting pristine rivers, turning bucolic farmlands into noisy industrial zones, and leaking enough methane to make ordinary tap water as flammable as lighter fluid. Bank is now bringing attention to yet another problem: radiation. Her research shows that high-pressure fluids striking the shale could dislodge naturally occurring radioactive compounds such as uranium and strontium, putting groundwater at risk of contamination.


“Shale is a garbage-bucket rock,” she says. “The more organically rich the shale is, the more natural gas is present, but the more other stuff is in there too.”

To determine how fracking fluids mobilize metals in the shale, Bank and her team solicited rock samples from drill sites in western New York and Pennsylvania. When the researchers subjected their samples to beamed ions—a high-precision way to dislodge surface chemicals—they confirmed that shale rocks contain a suite of toxic metals, including uranium, barium, chromium, zinc, and arsenic. Bank also discovered something new and disturbing: The metals were chemically bound to hydrocarbons, the organic compounds that make up natural gas. Separated from the rock, uranium or any other toxic metal could easily hitch a ride when the drilling wastewater is siphoned back to the surface, Bank found.

The newly tapped deposits in the Marcellus Shale have helped to more than double the nation’s estimated shale gas reserves, from 23 trillion cubic feet in 2007 to some 
60 trillion cubic feet in 2009.

“If the goal of fracking is to extract that organic matter—the natural gas—then you’re mobilizing the uranium as well,” she says. As a result, she believes, the current methods for cleaning wastewater generated by fracking are woefully inadequate. Right now, water is injected into disposal wells, dumped into evaporation pits, or run through drinking-water treatment facilities. “This water needs to be treated like industrial waste,” Bank says. Otherwise, radioactive material and a slew of other toxic compounds could leach into the groundwater, potentially tainting it for generations.

Bank’s discovery is just the latest twist in the convoluted tale of fracking, which neatly pits two environmental agendas against each other. Investigations by The New York Times last winter revealed that sewage-treatment plants processing fracking wastewater are discharging radioactive fluid into public waterways, in some cases upstream of intake sites for drinking water. “It’s long been known that the Marcellus Shale is a radioactive formation,” says Kate Sinding, a senior attorney with the Natural Resources Defense Council. “But these concerns have never been dealt with.”